Currently, the roam of a terminal user refers to that a mobile terminal user roams among different regions, and the roam of the mobile terminal user is seamless move, when the mobile terminal user moves, the network access point thereof can be changed at any time without interrupting the service session being conducted.
For the softswitch of the core control device in the next generation network structure, it is based on the packet switched data network, while the data network is not divided into distance and region, then the terminal user registers with the softswitch device worldwide. As for the softswitch, the processes to all terminal users are same. Currently, the softswitch does not conduct the processes in a different way according to the different access regions of the terminal user and the different network resources used.